Figure 6. Injection of cardiac progenitor cells with downregulated Dnmt3a attenuates myocardial remodeling in areas remote from the infarcted region.

Cardiac progenitor cells (CPCs) were first transfected with si-Dnmt3a and then injected in the border zone of infarcted mouse hearts after LAD ligature. Mice were sacrificed at 15 or 30 days for immunohistochemical analysis of remote heart sections. (A) Myocyte transverse area (μm²) at 30 days. Remote myocardial transverse sections were stained with rhodamine wheat germ agglutinin (WGA) and quantified in 400 cells per heart in 6 hearts per group. (B) Interstitial fibrosis measured by Picrosirius red staining at 15 and 30 days. Areas of collagen fibers are identified in red (original magnification, ×20) were normalized to tissue area. Average of interstitial fibrosis was quantified in 3–6 sections per heart. n = 8–10 hearts at 15 days; n = 5–8 hearts at 30 days. *P < 0.05 compared with control; Mann-Whitney test. (C) Cardiac capillary density measured by isolectin staining and normalized to myocyte cell number at 15 and 30 days after surgery. Average capillary density was quantified in 3 sections /heart. n = 7 hearts at 15 days; n = 5–6 hearts at 30 days. *P < 0.05 compared with control; Mann-Whitney test. (D) Inflammatory cell infiltrate measured by immunostaining of CD45 15 and 30 days after surgery. n = 7–10 hearts at day 15; n = 5–7 hearts at day 30. *P < 0.05; Mann-Whitney test.